The Evolution of Irradiated Planets: Application to Transits

Extending the theory we derived recently for HD209458b to different cases of strongly irradiated gaseous exoplanets, we have calculated the consistent evolution of the new transiting planet, OGLE-TR-56b, for its recently revised mass determination. The theory is shown to successfully reproduce the observed radius, for the proper age of the system. We also examine the dissipation of kinetic energy at the planet's internal adiabat due to atmospheric winds, and place constraints on the efficiency of this process. We show that a fraction $sim 0.1$ -- 0.5% of the incident flux transformed into thermal energy deposited at the adiabatic level can accommodate the observed radii of both OGLE-TR-56b and HD209458b. The present theory yields quantitative predictions on the evolution of the emergent spectrum and fundamental properties of hot-jupiters. The predictions for radius, luminosity, temperature as a function of the planet's mass and orbital distance can be used as benchmarks for future detections of transit planets.Comment: 8 pages, 4 figures, to be published in ApJ Letter